Discussion switches

# Open - Discussion: Read only mode

Pending our DB update tomorrow (26/11/2013), we realised we don't have any way of telling users that we are in read only mode.

This is a quick solution to that.

# Looky
![discussion-read-only](https://f.cloud.github.com/assets/31692/1613967/5f35b08e-55e2-11e3-9313-2141c9a0333e.png)

# Notes

* This has highlighted a design challenge of how we deal with states (read-only, signed-in). I have a few solutions but might want to run them through someone else's brain first